Customized multifocal ophthalmic lens

ABSTRACT

System and method for customizing multifocal ophthalmic lenses, such as an intraocular lens (IOL) or the like, that may be tailored for an individual patient or group of patients beyond the selection of a particular IOL power. One or more eye factors of the patient are determined, a set of different multifocal intraocular lenses having a similar base power are determined based on the eye factors, and a multifocal intraocular lens is selected for the patient from the set based on the eye factors.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/007,809, filed Dec. 13, 2007 and PCT Application No. PCT/US08/86827,filed Dec. 15, 2008.

BACKGROUND OF THE INVENTION Field of the Invention

This invention generally relates to optical correction, and in exemplaryembodiments provides methods, devices, and systems for mitigating ortreating defects of the eye. Among the exemplary embodiments, theinvention may provide multifocal intraocular lenses.

Background

Presbyopia is a condition that affects the accommodation properties ofthe eye. As objects move closer to a young, properly functioning eye,the effects of ciliary muscle contraction and zonular relaxation allowthe lens of the eye to become rounder or more convex, and thus increasethe optical power and ability of the eye to focus at near distances.Accommodation can allow the eye to focus and refocus between near andfar objects.

Presbyopia typically develops as a person ages, and is associated with anatural progressive loss of accommodation. A presbyopic eye often losesthe ability to rapidly and easily refocus on objects at varyingdistances. The ability to focus on objects at near distances may alsodiminish with the presbyopic eye. Although this condition progressesover the lifetime of an individual, the effects of presbyopia usuallybecome noticeable after the age of 45 years. By the age of 65 years, thecrystalline lens has often lost almost all elastic properties and hasonly a limited ability to change shape, or residual accommodation.Residual accommodation refers to the amount of accommodation thatremains in the eye. A lower degree of residual accommodation contributesto more severe presbyopia, whereas a higher amount of residualaccommodation correlates with less severe presbyopia.

Along with reductions in accommodation of the eye, age may also induceclouding of the lens due to the formation of cataracts. Cataracts mayform in the hard central nucleus of the lens, in the softer peripheralcortical portion of the lens, or at the back of the lens. Cataracts canbe treated by the replacement of the cloudy natural lens with anartificial lens. Phacoemulsification systems often use ultrasound energyto fragment the natural lens and aspirate the lens material from theeye. An artificial lens replaces the natural lens in the eye, with theartificial lens often being referred to as an intraocular lens (IOL).

After replacement of the natural lens with an intraocular lens, patientsmay have little or no ability to adjust the optical power associatedwith the optical tissues of the eye so as to maintain visual qualitywhen changing viewing distance (for example, between viewing a farobject while driving and viewing a near object while reading smallprint). Fortunately, a variety of technologies have been developed thatenhance the ability of IOLs to facilitate viewing objects at differentdistances. Multifocal IOLs may, for example, rely on a diffractiveoptical surface to direct portions of the light energy toward differingfocal distances, thereby allowing the patient to see both near and farobjects.

While generally successful at mitigating presbyopia, as with allsuccesses, still more improvements would be desirable. With existingmultifocal IOLs, the performance and patient satisfaction may depend onseveral aspects related to the individual patient. As a result, not allpatients are satisfied with multifocal IOLs after implantation for avariety of reasons.

In light of the above, it would be desirable to provide improved IOLsfor cataract patients and others. IOL lens design may include acompromise among various design objectives. It would be particularlybeneficial if these improved IOLs could take advantage of thecapabilities of diffractive multifocal optics, and would enhance patientsatisfaction by having optical attributes that are more tailored to theneeds and desires of the patient.

SUMMARY OF THE INVENTION

The present invention generally provides improved optical devices,systems, and methods, with exemplary embodiments providing improvedophthalmic lenses. Customized multifocal ophthalmic lenses, such asintraocular lenses (IOLs) and the like, may be tailored or selected foran individual patient or group of patients, rather than limiting theselection of the multifocal ophthalmic lens to a particular IOL power(e.g., a one-size-fits-all multifocal attempt at mitigation ofpresbyopia for a wide variety of patients using a single IOL structure).

In one embodiment, a system for producing a custom intraocular lens fora patient is provided. The system includes a memory and a processorcoupled to the memory. The memory is configured to store a firstdatabase of lifestyle parameters, a second database of eye factors, anda third database of multifocal intraocular lenses. The processor isconfigured to determine an add power based on the first database and thesecond database and select the custom intraocular lens from the thirddatabase based on the add power.

In another embodiment, a system is provided for producing a custommultifocal intraocular lens having a diffractive surface with one ormore echelettes. The system includes a memory and a processor coupled tothe memory. The memory is configured to store a first database oflifestyle parameters and a second database of eye factors. The processoris configured to determine at least one characteristic of the one ormore echelettes based on the first database and the second database andselect a diffractive multifocal intraocular lens based on the at leastone characteristic.

In another embodiment, a method of producing a multifocal intraocularlens for a patient is provided including determining one or more eyefactors of the patient, determining a set of different multifocalintraocular lenses based on the one or more eye factors of the patient,and selecting the multifocal intraocular lens for the patient from theset of multifocal intraocular lenses based on the one or more eyefactors of the patient. The multifocal intraocular lenses of the set ofhave a similar base power.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, wherein like reference numerals refer to similarcomponents:

FIG. 1 schematically illustrates an exemplary embodiment of anintraocular lens incorporating aspects of the present invention;

FIGS. 2-3 graphically illustrate optical performance, at differingviewing distances, of multifocal diffractive intraocular lenses havingdiffering characteristics that may be suitable for differing patients;and

FIG. 4 is a block diagram of an exemplary embodiment of a system forcustomizing a multifocal lens.

DETAILED DESCRIPTION

The present invention generally provides improved ophthalmic devices,systems, and methods. In exemplary embodiments, the invention providesmultifocal ophthalmic lenses (e.g., intraocular lenses (IOLs) and thelike) that employ refractive and/or diffractive techniques, and that arecustomized for a particular patient or patient population subgroup.Rather than being limited to selection of a particular IOL power (whichtypically represents a one-size-fits-all multifocal attempt atpresbyopia mitigation for a wide variety of patients using a single IOLstructure), the multifocal lens design is tailored or selected for anindividual patient or group of patients. For example, a multifocalintraocular lens may be selected for the patient from among a set ofappropriate multifocal intraocular lenses based on one or more patientparameters. As part of determining the appropriate multifocalintraocular lenses for the set, one or more IOLparameters/characteristics may be selected for emphasis or weightingbased on the patient parameter(s).

Some examples of patient parameters that may be considered duringselection, design, and/or fabrication of the custom multifocal IOLsdescribed herein include, but are not necessarily limited to: estimatedpost-operative pupil size or sizes, optionally under different viewingconditions including differing lighting conditions (e.g., photopic,mesopic, or the like) and/or differing viewing distances (e.g., near,far, or the like); age; cataract grade; lifestyle assessment of thepatient's vision needs (such as based on a questionnaire, physicianassessment, or the like); shape of the cornea; length of the eye;anterior chamber depth; historic refraction; medical status of theretina; any combinations thereof; and the like.

Some IOL parameters that may be changed (or that may differ amongselectable alternative IOLs) or emphasized for different patientsinclude, but are not necessarily limited to: aberration correction; addpower(s) for far, near, and/or intermediate focus; depth of focus of oneor more focal points; intermediate vision; spectral light transmissioncharacteristics (e.g., violet, blue, ultraviolet (UV) blockers, or thelike); pupil dependent characteristics (such as a central zone size, oneor more of the foregoing parameters as based on the pupil, or the like);and/or other parameters.

A variety of multifocal intraocular lenses employing refractive and/ordiffractive techniques can be customized for a particular patient orpatient population subgroup and/or utilized for selective population ofa group or database of lenses particularly suited for the patient orpatient population subgroup. An exemplary customized intraocular lensfor a particular patient may, for example, comprise a pupil-dependentbifocal diffractive intraocular lens 10, as schematically illustrated inFIG. 1. The lens 10 has a central portion 11 that includes a bifocaldiffractive structure 12 producing a 50:50 split of the incoming lightenergy, with about an even distribution between the light energy beingdirected to a first focal length and the light energy being directed toa different focal length. Examples of diffractive IOL structures aredescribed, for example, in U.S. Pat. No. 5,144,483, and in U.S. Pat. No.4,881,804, and examples of refractive multifocal intraocular lenses aredescribed in U.S. Pat. Nos. 6,527,389; 5,225,858; and 6,557,998. Each ofthese references is incorporated herein by reference, and someembodiments may employ one or more structures similar to (or derivedfrom) those described by U.S. Pat. Nos. 4,881,804; 5,144,483; 6,527,389;5,225,858; and 6,557,998. Other multifocal intraocular lenses havingrefractive and/or diffractive elements may also be used forcustomization or selection to populate a desired group of lenses (e.g.,meeting predetermined criteria for the particular patient).

A peripheral portion 14 of the lens 10 may include a monofocal structurethat directs substantially all of the light incident thereon to a singlefocal length. In one embodiment, the differing focal lengths of thecentral portion 12 include a near focus and a far focus, and themonofocal peripheral portion 14 directs light to the far focus. Thediameter of the central portion 12 is in a range from about 1 mm toabout 6 mm.

As the eye adjusts to different viewing conditions (including bothdifferent levels of lighting and different viewing distances), the pupilof the eye often varies in size. Different patients have different pupilsizes. Additionally, the constriction or change in pupil size ofpatients typically varies, so that two patients that have the same pupilsize when viewing the same distant objects under low light conditionsmay have differing pupil sizes when viewing the same near objects underbright light.

In an exemplary embodiment, the central portion 12 has a size, such as adiameter 16, that is tuned to maximize the performance of the lens 10for an individual patient or group of patients based at least in part onthe patient pupil size. A lens having a smaller central portion may beselected for patients having smaller pupils, and a lens having a largercentral portion may be selected for patients having larger pupils.

In the exemplary embodiment of the lens 10, a specific lens design maybe chosen based on estimated post-operative pupil sizes. Pupil sizes forthe patient post-procedure (such as IOL insertion and/or cataractremoval) can be estimated based on preoperative pupil sizes, patientage, the grade of cataract, the type of surgical procedure that isplanned, and other factors. Empirical studies in which measurements ofpupils are taken before and after surgery for patients of differentages, grade of cataracts, and the like, may be employed. Alternativeembodiments may employ lens types that can be adjusted post-operatively,such as structures analogous to or derived from a Calhoun lens. Whenusing such structures, the post-operative pupil size can be measured andthe lens adjusted accordingly.

Alternative embodiments may be designed specifically to allow or enhancepostoperative ophthalmic treatments, such as laser assisted refractivesurgery, or to effect a desired optical outcome in combination withadditional ophthalmic lenses (e.g., eyeglasses, contact lenses,intracorneal implants or inserts, and the like). For example, laserassisted refractive surgery may be used to fine-tune the refraction orto extend the depth of focus. Combinations with additional ophthalmiclenses may comprise the use of corneal inlays, contact lenses, orspectacles, in order to fine-tune the optical characteristics, or toalter the image magnification on the retina.

Regarding the interaction between pupil sizes under different viewingconditions and the size of the central portion so as to mitigatepresbyopia, analogous approaches for presbyopia correction using patientdata are described in U.S. Pat. Publication No. 2004/0169820 in the nameDai et al., the full disclosure of which is incorporated herein byreference. For example, a prescription may be established that mitigatesor treats presbyopia for the particular patient, and the shape of themultifocal intraocular lens may be designed or selected to correspond tothe optical shape associated with this prescription. Some embodiments ofthe lens 10 may have optical or other characteristics as described inU.S. Pat. Publication No. 2004/0169820, although other embodiments omitthe same. For example, some embodiments of the lens 10 may have opticalor other characteristics associated with one or more of the ablationshapes for mitigating presbyopia described in U.S. Pat. Publication No.2004/0169820.

Note that the lens 10 need not necessarily be limited to a bifocal lensembodiment. Other embodiments that may employ aspects of the presentinvention include trifocal lenses, aspheric lenses, and the like. Forexample, aspheric IOLs are described in U.S. Pat. No. 6,609,793 in thename of Norrby et al., in U.S. Pat. Publication No. 2004/0156014 in thename of Piers et al., and in other references. Both of theabove-referenced applications are incorporated herein by reference.Related approaches for mitigation and/or correction of presbyopia usingpatient data may also employ multifocal apodization, such as describedin U.S. Pat. No. 5,699,142, in the name of Lee et al. (also incorporatedherein by reference), as well as other apodized multifocal approaches.

Techniques and approaches developed for contact lenses may also beemployed in some aspects of the present invention. For example, thedesign of the contact lens characteristics described in U.S. Pat.Publication No. 2004/0085515, the disclosure of which is incorporatedherein by reference, may be employed to customize the opticalcharacteristics of the multifocal intraocular lens for the patient.

Some embodiments may benefit by using lower add power in the centralportion 11. Lowering add power can result in an increased (e.g.,farther) reading distance and improved viewing of intermediatelypositioned objects. The modulation transfer function (MTF) may besomewhat lower, and less halo and scatter can occur when the add poweris limited to less than 3 D, the add power often being less than 2.5 Dand optionally being 2 D or less.

Referring to FIGS. 2 and 3, optical performance, at differing viewingdistances, of different multifocal diffractive intraocular lenses aregraphically illustrated. Each of these intraocular lenses havecharacteristics that may be suitable for different patients. FIG. 2 is athrough-focus plot of modulation transfer functions (MTFs) 20, 22, 24,26 at 50 line pairs per mm (or, equivalently, cycles per mm or c/mm) fordifferent multifocal diffractive IOLs at a first pupil size (e.g., about3 mm). This pupil size may correspond with a normal viewing condition. Afirst MTF 20 is associated with a diffractive multifocal IOL without addpower. A second MTF 22 is associated with a diffractive multifocal IOLwith about 3.5 D of add power. A third MTF 24 is associated with adiffractive multifocal IOL with about 2 D of add power. A fourth MTF 26is associated with a diffractive multifocal IOL with about 1 D of addpower. The fourth MTF 26 associated (with the relatively lower addpower) indicates a region of extended depth of focus, in comparison withthe other MTFs 20, 22, 24.

FIG. 3 is a through-focus plot of modulation transfer functions (MTFs)30, 32, 34, 36 for different multifocal diffractive IOLs at a secondpupil size (e.g., about 5 mm). In contrast with the first pupil size(associated with the MTFs 20, 22, 24, 26 shown in FIG. 2), this pupilsize may correspond with a lower lighting viewing condition comparedwith the normal viewing condition. A first MTF 30 is associated with adiffractive multifocal IOL without add power. A second MTF 32 isassociated with a diffractive multifocal IOL with about 3.5 D of addpower. A third MTF 34 is associated with a diffractive multifocal IOLwith about 2 D of add power. A fourth MTF 36 is associated with adiffractive multifocal IOL with about 1 D of add power. The fourth MTF36 (with the relatively lower add power) indicates a region of extendeddepth of focus, in comparison with the other MTFs 30, 32, 34, underlower lighting viewing conditions.

As best shown in FIGS. 2 and 3, each of the corresponding multifocaldiffractive IOLs have different properties corresponding with differentoptical performances. A variety of structural elements may be used toproduce the desired multifocal diffractive IOL. For example, adiffractive pattern with a relatively low add power may be imposed onone shape to define the overall form of a posterior surface of theoptic. The preceding embodiments are merely for illustrative purposes,and should not be construed as limiting in any way. The parameters ofthe multifocal diffractive IOL may also be adjusted to suit a particularset of design objectives or to reflect a particular set of measurementsfor a particular set of eyes or an individual eye. For example, thefactors for the eye may be selected or weighted for priorityconsideration in the IOL design based on statistical averages for aparticular population. In addition, the design of the diffractiveelement may be adjusted to provide a predetermined visual responsewithin the eye of a subject or patient.

Many of the methods, devices, and systems described herein will takeadvantage of an optical characteristic of the eye or eye factor.Exemplary eye factors include one or more measurements of the eye (e.g.,a pupil diameter at a predetermined viewing condition), a set of pupildiameters each associated with a different predetermined viewingcondition, a corneal shape of the anterior corneal surface (e.g.,measured by corneal topography and/or by a keratometer), a corneal shapeof the posterior corneal surface (e.g., measured by Scheimpflugphotography using a Pentacam™ measurement system or the like), a lengthof the eye (e.g., the axial length of the eye as measured using A-scanbiometry, Laser Interference Biometry such as with the IOLMaster™, orthe like), an anterior chamber depth, and/or the patient's historicrefraction. A wide variety of measurement devices may be used to obtainthese or other optical characteristics of the patient's eye useful forthe presbyopia mitigation described herein.

Effective presbyopia mitigation for a particular patient may alsobenefit from data regarding the lifestyle of that patient or lifestyleparameters. Such patient lifestyle parameters may be identified bymeasurements, observations, questionnaires from the patient or others incontact with or having knowledge about the patient, and the like. Thepatient lifestyle parameters may be stored in a memory having anupdateable database. Exemplary patient lifestyle parameters may includeor indicate a preferred reading distance, a preference for readingvision or intermediate vision, an occupation, hobbies, an amount and/ortype of outdoor activity, an amount of reading time, an amount ofcomputer time, a work environment, and/or the like. Additionally, one ormore of the patient lifestyle parameters may be selected for emphasis(e.g., using a weighting format) when customizing the lenscharacteristics to the patient.

Based on the eye factors and lifestyle parameters, one or more suitablerefractive prescription lenses may be selected and/or designed for aparticular presbyopia patient so as to mitigate the disadvantages ofpresbyopia for that patient. In one embodiment, the prescriptive lensincludes a diffractive multifocal lens, and a variety of lens parametersmay be determined and/or selected. For example, the diffractivemultifocal lens can have one or more echelettes. The term echelette isreferred to herein as a generally V-shaped groove formed on the lenssurface. Examples of lens parameters include a lens profile height, thediameters associated with the echelettes, the echelette profile shape,and the like. Additionally, the design may, for example, be pupildependent, and the profile height may vary for each echelette. Eachechelette may also have a different diameter. In addition, with pupildependent designs or other designs emphasizing specific patient desires(e.g. for a patient highly valuing an extended depth of focus), one ormore of the echelette diameters may be different from those of moreconventional diameters and designs. Furthermore, with pupil dependentdesigns, the profile shape can be selected to be different for eachechelette.

Other lens parameters may also be determined in response to the eyefactors or lifestyle parameters, including but not necessarily limitedto spectral transmission characteristics, spherical aberrationcorrection, induced negative spherical aberration for mitigation ofpresbyopia (e.g., U.S. Pat. No. 7,261,412, the disclosure of which isincorporated herein by reference), cylinder (such as a toric multifocallens), and/or corneal coma correcting optical elements. Cylindercorrection and coma correction may also be considered as aberrationcorrections. Still further variations and alternative lenscharacteristics and parameters may be included, including biconvexshapes, a diffractive profile(s) on anterior and/or posterior lenssurface, etc.

The present invention also provides systems for customizing oroptimizing a multifocal IOL for a patient to mitigate presbyopia orother vision conditions of the patient. For example, as shown in FIG. 4,a system 50 can be used for selecting or designing a multifocal IOL. Thesystem 50 includes an input 54 (e.g., a user interface such as a displaywith an input device (e.g., touch-sensitive screen, mouse, touchpad,keyboard, or the like) that accepts one or more patient lifestyleparameters and one or more eye factors associated with a patient, amemory 52 coupled to the input 54 that stores the patient lifestyleparameters and eye factors, and a processor 56 coupled to the input 54and the memory 52. The memory 52 may additionally store a database ofmultifocal IOLs for the patient, which can be populated via the input 54or by a candidate selection process performed by the processor 56.

The processor 56 includes computer hardware and/or software, oftenincluding one or more programmable processor units running machinereadable program instructions or code for implementing some or all ofone or more of the methods described herein. In one embodiment, the codeis embodied in a tangible media such as a memory (optionally a read onlymemory, a random access memory, a non-volatile memory, or the like)and/or a recording media (such as a floppy disk, a hard drive, a CD, aDVD, a memory stick, or the like). The code and/or associated data andsignals may also be transmitted to or from the processor 56 via anetwork connection (such as a wireless network, an Ethernet, aninternet, an intranet, or the like), and some or all of the code mayalso be transmitted between components of the system 50 and within theprocessor 56 via one or more bus, and appropriate standard orproprietary communications cards, connectors, cables, and the like canbe included in the processor 56.

The processor 56 is preferably configured to perform the calculationsand signal transmission steps described herein at least in part byprogramming the processor 56 with the software code, which may bewritten as a single program, a series of separate subroutines or relatedprograms, or the like. The processor 56 may include standard orproprietary digital and/or analog signal processing hardware, software,and/or firmware, and has sufficient processing power to perform thecalculations described herein during treatment of the patient. Theprocessor 56 optionally includes a personal computer, a notebookcomputer, a tablet computer, a proprietary processing unit, or acombination thereof. Standard or proprietary input devices (such as amouse, keyboard, touchscreen, joystick, etc.) and output devices (suchas a printer, speakers, display, etc.) associated with modern computersystems may also be included with the system 50, and additionalprocessors having a plurality of processing units (or even separatecomputers) may be employed in a wide range of centralized or distributeddata processing architectures.

In this embodiment, the processor 56 determines or selects a particularmultifocal IOL based on the patient lifestyle parameters and one or moreeye factors. For example, the processor 56 can determine at least onecharacteristic of the echelettes associated with a candidate multifocalIOL based on the patient lifestyle parameters and the eye factors. Adiffractive multifocal IOL can then be selected based on thischaracteristic(s). One or more of the patient lifestyle parametersand/or eye factors may be weighted by the processor 56 for priorityconsideration (e.g., to determined the desired characteristic of thecandidate multifocal IOL) when selecting or determining the particularmultifocal IOL for the patient. In this embodiment, the processor 56includes a processing module 58 that determines an add power based onthe patient lifestyle parameters and one or more eye factors. The module58 may be a separate processing unit from the processor 56 in otherembodiments.

In another embodiment, the system 50 may be communicate with a lasersystem (not shown) that directs laser energy onto a surface of thecornea according to a pre-determined ablation profile to reprofile asurface of the cornea. This is particularly useful for combinedophthalmic treatments to effect a desired optical correction. Forexample, the ablation profile and the determined multifocal IOLcharacteristics are together considered for mitigating presbyopiaassociated with the patient's eye or for implementing other opticalcorrections.

The present invention also provides methods of providing improvedophthalmic lenses. In general, at least one characteristic of thepatient's eye is measured, and a multifocal intraocular lens (e.g., adiffractive multifocal intraocular lens) is selected from among aplurality of multifocal intraocular lenses having similar IOL powersbased on the measured characteristic of the eye of the patient. At leastsome of these intraocular lenses have central portions, and selection ofthe intraocular lens includes selecting between different centralportion sizes.

In one embodiment, the method includes determining a set of patientlifestyle parameters for a patient (e.g., by measurements, observations,and questionnaires from the patient or others in contact with or havingknowledge about the patient, or the like), determining at least one eyefactor for an eye of the patient (e.g., via measurement, retrieved froma database, or the like), determining an add power based on thelifestyle parameter(s) and the eye factor(s), and selecting a multifocalintraocular lens for the patient based on this add power. The eyefactors can include an axial length of the eye (e.g., for determiningthe add power in response to a preferred reading distance and the axiallength of the eye), the corneal shape of the eye, the pupil diameter ofthe eye under a predetermined viewing condition, a set of pupildiameters of the eye under a set of predetermined viewing conditions, akeratometry factor, and/or a corneal radius of curvature factor.Additionally lifestyle parameters include, but are not necessarilylimited to, an amount of outdoor activity, an amount of reading time, anamount of computer time, and a work environment.

In another embodiment, based on at least one eye factor, a base power ofthe multifocal intraocular lens is selected in addition to a separatemultifocal lens parameter (e.g., an amount of add power, a depth offocus characteristic, an amount of aberration selected to at leastpartially correct for an aberration of the cornea of the patient's eye,a spectral transmission characteristic, a pupil dependent add powerfunction) for a multifocal intraocular lens. Additional eye factorsinclude, but are not necessarily limited to, a patient age, a cornealshape, a cataract grade, an estimated postoperative pupil diameter ofthe eye under predetermined viewing conditions, or a pre-existingintraocular lens.

An exemplary embodiment of a selection of a multifocal intraocular lensincludes determining at least one eye factor for an eye of the patient.Based on the at least one eye factor, a base power and/or a multifocallens parameter is selected for a multifocal intraocular lens. As a morespecific example, for many method embodiments, an IOLpresbyopia-mitigating add power is determined using a standard orcustomized near (e.g. reading) viewing distance of the patient. However,the effectiveness of the IOL add power is also determined by thepatient's eye dimensions, and primarily by the axial length of the eye.For an eye with an average axial length, a 4 D add may, for example,deliver a near focus at about 33 cm. For an eye with a longer axiallength, the desired add power may be larger. For a patient having asubstantially standard eye length of about 23.5 mm, with a substantiallystandard cornea, a 21.7 D IOL base power may be suitable. For thispatient, a 4 D add results in a near distance of about 32.1 cm. For anotherwise similar patient with similar corneal characteristics and aneye with an axial length of about 27.5 mm, the anterior chamber depthwill typically be larger, and the patient may instead benefit from abase power of about 9.1 D. To have a reading distance of about 32 cm,this other patient may benefit from about a 5.1 D add power formitigation of myopia. Note that the base power is normally selectedbased on the axial length of the eye and the corneal curvature (two eyefactors).

Exemplary methods for customized mitigation of the presbyopia of aparticular patient will also often include determining at least onepatient lifestyle parameter of the patient. Based on the at least onelifestyle parameter and the at least one eye factor, a base power and amultifocal lens parameter for a multifocal intraocular lens can then beselected. A more specific example of such embodiments might be a patientwho is an active philatelist or stamp collector. Such a patient may, forexample, prefer to have a best near vision at a distance of about 20centimeters. For this patient, an add power of about 5 D might be chosento achieve the best performance for this patient so as to mitigate theirpresbyopia for their lifestyle. In contrast, a patient who is an activegolfer may wish to instead have a best near vision at a distance ofabout 1.5 m. An add power of about 1 D could be chosen to achieve anoptimal performance for this patient. Patients for whom day and/or nightdriving or other activities are particularly important, or who wouldhave different lifestyle priorities that may impact their desired visualperformance, may similarly have their vision customized (i.e., via theselected multifocal intraocular lens) in response to their lifestyleparameters so as to effectively mitigate the impacts of presbyopia ontheir lives.

While the exemplary embodiments have been described in some detail, byway of example and for clarity of understanding, those of skill in theart will recognize that a variety of modification, adaptations, andchanges may be employed. Hence, the scope of the present inventionshould be limited solely by the appending claims.

What is claimed is:
 1. A system (50) for producing a custom intraocularlens for a patient, the system comprising: a memory (52) configured tostore a first database of lifestyle parameters, a second database of eyefactors, and a third database of multifocal intraocular lenses; aprocessor (56) coupled to the memory and configured to: determine an addpower based on the first database and the second database; and selectthe custom intraocular lens from the third database based on the addpower.
 2. The system of claim 1, wherein the processor is furtherconfigured to: apply a predetermined weighting to the lifestyleparameters of the first database and the eye factors of the seconddatabase to produce a first weighted database of lifestyle parametersand a second weighted database of eye factors; and determine the addpower based on the first weighted database and the second weighteddatabase.
 3. The system of claim 1, wherein at least some of themultifocal intraocular lenses have a first intraocular lens power, andwherein at least some of the multifocal intraocular lenses havedifferent optical characteristics, and wherein the custom intraocularlens is configured to mitigate a presbyopia of the particular patient.4. The system of claim 1, wherein the first database comprises apreferred reading distance of the patient.
 5. The system of claim 4,wherein the second database comprises an axial length of an eye, andwherein the processor is further configured to determine the add powerbased on the preferred reading distance and the axial length of the eye.6. The system of claim 1, wherein the second database comprises one ormore eye factors selected from a group consisting of a corneal shape ofan eye, a pupil diameter of an eye for a predetermined viewingcondition, a set of pupil diameters of an eye under a set ofpredetermined viewing conditions, an axial length of an eye, akeratometry factor, and a corneal radius of curvature factor.
 7. Thesystem of claim 1, wherein the processor is further configured to selectthe custom intraocular lens from the third database based on the addpower and a treatment to an eye, the treatment subsequent to aninsertion of the custom intraocular lens into the eye.
 8. The system ofclaim 7, wherein the custom intraocular lens has one or morecharacteristics, and wherein the treatment comprises an adjustment to atleast one of the one or more characteristics of the custom intraocularlens.
 9. The system of claim 7, wherein the eye with the customintraocular lens has a refraction, and wherein the treatment comprisesan adjustment to the refraction.
 10. The system of claim 7, wherein thetreatment comprises a laser assisted refractive ophthalmic surgery. 11.A system (50) for producing a custom multifocal intraocular lens havinga diffractive surface with one or more echelettes, the systemcomprising: a memory (52) configured to store a first database oflifestyle parameters and a second database of eye factors; a processor(58) coupled to the memory and configured to: determine at least onecharacteristic of the one or more echelettes based on the first databaseand the second database; and select a diffractive multifocal intraocularlens based on the at least one characteristic.
 12. The system of claim11, wherein the at least one characteristic comprises one or morecharacteristics selected from a group consisting of one or more heightsof the one or more echelettes, one or more diameters of the one or moreechelettes, and one or more profile shapes of the one or moreechelettes.
 13. The system of claim 11, wherein the second databasecomprises one or more eye factors selected from a group consisting of acorneal shape of an eye, a pupil diameter of the eye for a predeterminedviewing condition, an axial length of the eye, a keratometry factor, anda corneal radius of curvature factor.
 14. The system of claim 11,wherein the first database comprises a preferred reading distance,wherein the second database comprises an axial length of an eye, andwherein the processor is further configured to determine the at leastone characteristic in response to the preferred reading distance and theaxial length of the eye.
 15. The system of claim 11, wherein theprocessor is further configured to select the diffractive multifocalintraocular lens based on the at least one characteristic and atreatment to an eye, the treatment subsequent to an insertion of thediffractive multifocal intraocular lens into the eye.
 16. The system ofclaim 15, wherein the diffractive multifocal intraocular lens has one ormore characteristics, and wherein the treatment comprises an adjustmentto at least one of the one or more characteristics of the diffractivemultifocal intraocular lens.
 17. The system of claim 15, wherein the eyewith the diffractive multifocal intraocular lens has a refraction, andwherein the treatment comprises an adjustment to the refraction.
 18. Thesystem of claim 15, wherein the treatment comprises a laser assistedrefractive ophthalmic surgery.
 19. A method of producing a multifocalintraocular lens for a patient, the method comprising the steps of:determining one or more eye factors of the patient; determining a set ofdifferent multifocal intraocular lenses based on the one or more eyefactors of the patient, the set of multifocal intraocular lenses havinga similar base power; and selecting the multifocal intraocular lens forthe patient from the set of multifocal intraocular lenses based on theone or more eye factors of the patient.
 20. The method of claim 19,wherein at least some multifocal intraocular lenses of the set ofmultifocal intraocular lenses have central portions with associatedsizes and add powers, and wherein the step of selecting comprisesselecting a first multifocal intraocular lens from the set of multifocalintraocular lenses, the first multifocal intraocular lens has a centralportion and an add power both based on the one or more eye factors ofthe patient.
 21. The method of claim 19, wherein the selecting stepcomprises selecting a diffractive multifocal intraocular lens for thepatient from the set of multifocal intraocular lenses based on the oneor more eye factors of the patient.
 22. The method of claim 19, furthercomprising determining an add power of the multifocal intraocular lensfor the patient based on one or more lifestyle parameters of the patientand the one or more eye factors of the patient, and wherein theselecting step comprises selecting the multifocal intraocular lens forthe patient based on the add power.
 23. The method of claim 22, whereinthe one or more eye factors comprise an axial length of the eye, andwherein the step of determining an add power comprises determining theadd power based on one or more of eye factors selected from a groupconsisting of a corneal shape of the eye, a pupil diameter of the eyefor a predetermined viewing condition, a keratometry factor, a cornealradius of curvature factor, a preferred reading distance and the axiallength of the eye.
 24. The method of claim 19, wherein the multifocalintraocular lens for the patient has a diffractive surface with one ormore echelettes, wherein the method further comprises determining atleast one characteristic of one or more echelettes based on a set oflifestyle parameters of the patient and an eye factor of the patient,and wherein the selecting step comprises selecting the diffractivemultifocal intraocular lens from the set of multifocal intraocularlenses based on the at least one characteristic of the one or moreechelettes.
 25. The method of claim 24, wherein the at least onecharacteristic comprises one or more characteristics selected from agroup consisting of one or more heights of the one or more echelettes,one or more diameters of the one or more echelettes, and one or moreprofile shapes of the one or more echelettes.
 26. The method of claim19, further comprising determining at least one patient lifestyleparameter of the patient, and wherein the selecting step comprisesselecting one or more multifocal lens parameters for the multifocalintraocular lens based on the at least one lifestyle parameter and theone or more eye factors.
 27. The method of claim 26, wherein the one ormore multifocal lens parameters comprises one or more parametersselected from a group consisting of an add power amount, a depth offocus characteristic, an aberration amount selected to at leastpartially correct for an aberration of the cornea of the eye, a spectraltransmission characteristic, and a pupil dependent add power function.28. The method of claim 26, wherein the one or more eye factorscomprises one or more factors selected from a group consisting of apatient age, a corneal shape, a cataract grade, an estimatedpostoperative pupil diameter of the eye for a predetermined viewingcondition, and a pre-existing intraocular lens.
 29. The method of claim26, wherein the at least one lifestyle parameter comprises one or moreparameters selected from a group consisting of an amount of outdooractivity, an amount of reading time, an amount of computer time, and awork environment.
 30. The method of claim 19, wherein the selecting stepfurther comprises selecting the multifocal intraocular lens based on theone or more eye factors and a treatment to an eye subsequent to aninsertion of the multifocal intraocular lens into the eye.
 31. Themethod of claim 19, wherein the multifocal intraocular lens has one ormore characteristics, and wherein the selecting step further comprisesselecting multifocal intraocular lens based on the one or more eyefactors and a treatment to an eye subsequent to an insertion of themultifocal intraocular lens into the eye, the treatment comprising anadjustment to at least one of the one or more characteristics of themultifocal intraocular lens.
 32. The method of claim 19, wherein the eyewith the multifocal intraocular lens has a refraction, and wherein theselecting step further comprises selecting the multifocal intraocularlens based on the one or more eye factors and a treatment to an eyesubsequent to an insertion of the multifocal intraocular lens into theeye, the treatment comprising an adjustment to the refraction.
 33. Themethod of claim 19, wherein the selecting step further comprisesselecting the multifocal intraocular lens based on the one or more eyefactors and a treatment to an eye subsequent to an insertion of themultifocal intraocular lens into the eye, the treatment comprising alaser assisted refractive ophthalmic surgery.